This invention relates to a molding device, particularly to a molding device adapted to mold box-like modular concrete units having large assembled formwork boards that can be removed entirely from the molded concrete structure and resetted quickly at the next location.
Molding devices of the above described type have existed in various forms. U.S. Pat. No. 2,544,297 discloses an inner collapsible form having multiple plate parts interconnected at corners by means of locking devices. The inner form collapses and is released from the molded structure when the corner plate parts are unlocked. U.S. Pat. No. 3,614,054 discloses an inner form with a core frame incorporating means for collapsing and stripping the inner form from the molded structure. U.S. Pat. No. 3,934,808 discloses an inner form having side panels, end panels and corner panels. The corner panels can be pulled inward by a central single power means through a center linkage mechanism to leave a space between the adjacent side panel and end panel so that the whole inner form contracts. French Pat. No. 2489206 discloses an inner form having internal wall shutters and wedge-shaped corner pieces which can be pulled inward by individual power means. The wedge-shaped corner pieces are not connected to the shutters and move individually independently of the shutters.